What Is the Soap Manufacturing Process?

Soap is a general term for fatty acid metal salts. The general formula is RCOOM, where RCOO is a fatty acid radical and M is a metal ion. The fatty acid carbon number in daily soap is generally 10-18. The metals are mainly alkali metals such as sodium or potassium, and ammonia and certain organic bases such as ethanolamine and triethanolamine are also used to make special purpose soaps. In a broad sense, fatty acid salts obtained by saponification or neutralization of base oils, waxes, rosins, or fatty acids with alkalis can be referred to as soaps. Soap is soluble in water and has a washing and decontaminating effect. There are various types of soaps, which are also called toilet soap, metal soap and compound soap.

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The molecular structure of soap can be divided into two parts. One end is a charged COO- (hydrophilic site) and the other end is a non-polar carbon chain (oleophilic site). Soap can destroy the surface tension of water. When soap molecules enter the water, the polar hydrophilic parts will destroy the attraction between the water molecules and reduce the surface tension of the water. Clothing or skin surface. The lipophilic part of the soap penetrates deep into the oil, and the hydrophilic part dissolves in water. This combination forms a small oil droplet after being agitated, and the surface is covered with the hydrophilic part of the soap without re-aggregating into a large oil. . This process (also known as emulsification) is repeated many times, then all the oil stains will become very tiny oil droplets dissolved in water, which can be easily washed away.

The main ingredients are

An artificial detergent appeared in the soap in the Song Dynasty. Natural soap pods (also known as saponins, hanging knives, soap pods, commonly known as saponins) were smashed and ground, and spices were added to make orange-sized soap. Spherical, specially used for washing face and bath, commonly known as "soap ball". The Song Dynasty Zhou Mi "Old Martial Arts" Volume VI "Little Broker" records that Linan, Kyoto in the Southern Song Dynasty, already had businessmen who specialized in "soap groups." Ming Shi Lizhen's Compendium of Materia Medica recorded the manufacturing method of "soap balls": in the mountains of soap pods, the trees are tall, leaves such as sandalwood and acacia leaves, bloom in May and June, the pods are three or four inches thick, fleshy, with Number of sunspots, as big as a finger, not round, some

Soap is used for a wide range of applications, in addition to the familiar washing of clothes, it is also widely used in the textile industry. Usually the most commonly used is the higher fatty acid sodium salt, commonly called hard soap; the potassium salt is called soft soap, mostly used for shampooing and shaving. Its ammonium salt is commonly used as vanishing cream. According to the composition of the soap, from the perspective of the fatty acid part, soaps made from fatty acids with high saturation are relatively hard; on the other hand, soaps made from fatty acids with high saturation are relatively soft. The main raw material of soap is oil with higher melting point. Considering the length of the carbon chain, generally speaking, the carbon chain of the fatty acid is too short, the soap made is too soluble in water; if the carbon chain is too long, the solubility is too small. Therefore, only potassium salts or sodium salts of C10 to C20 fatty acids are suitable for soap. In fact, the sodium salts of C16 to C18 fatty acids are the most in soaps.

Soap also usually contains a lot of water. After adding spices, dyes and other fillers to the finished product, various soaps are obtained.

The commonly used yellow laundry soap is generally mixed with rosin. Rosin is added in the form of sodium salt. The purpose is to increase the solubility of the soap and foam, and it is also cheaper as a filler.

White laundry soap is added with sodium carbonate and water glass (the content can reach 12%), and the ingredients of general laundry soap contain about 30% moisture. If you dry the white laundry soap and cut it into thin slices, you get

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The composition of soap is sodium stearate (C17H35COONa). Sodium stearate is ionized by water in water to form stearate ions and sodium ions. In general, there are a lot of calcium and magnesium ions in hard water, and the stearate ions will combine with magnesium ions and calcium ions to form magnesium stearate and calcium stearate. Both calcium stearate and magnesium stearate are insoluble. The precipitation of water, so if soap is put into hard water, precipitation will occur. However, there is no or a small amount of magnesium ions and calcium ions in soft water. Therefore, if soap is put into soft water, there will be no precipitation, and the water is pure and transparent.

In fact, in addition to calcium and magnesium ions, soap can also be precipitated by iron, manganese, zinc, copper, etc. Therefore, it is defined chemically: Any mineral ion that can be precipitated by soap in water is called hardness ion . From this, it can be seen that the hardness refers to the index value of the total concentration of all hardness ions. However, in general natural water (including tap water), except for calcium and magnesium ions, the remaining amount of hardness ions is very small, so the hardness of water can be said to be a comprehensive characteristic represented by the concentration of calcium and magnesium ions in water.